In the modern office environment and other work locations, the need for electrical power is ever increasing. Furthermore, several separate electrical circuits may be required in one area to accommodate various types of equipment such as computers, communication equipment and the like on independent electrical circuits. The circuit requirements are generally such that for some circuits a ground conductor may be shared whereas for other circuits, e.g., certain computer equipment, an isolated ground circuit may be required. In a similar fashion, some circuits having separate positive conductors may share a common or neutral conductor whereas for other circuits separate positive and common conductors are required. Typical known multiple circuit arrangements provide a power junction block or the like with a plurality of terminals representing a plurality of circuits.
One prior art arrangement as described, for example, in U.S. Pat. No. 4,367,370, dated Jan. 4, 1983, discloses an outlet receptacle block having a ground terminal, a common terminal, and three positive terminals for engaging corresponding terminals of a junction block. The ground and common terminals are connected to the ground and common receptacle output terminals for engagement with the prongs of a standard three-prong electrical cord. The receptacle block further includes a switch which selectively connects one of the three positive prongs to the positive receptacle outlet connector, internal to the outlet receptacle block.
In another prior art arrangement disclosed in U.S. Pat. No. 4,666,223, dated May 19, 1987, an outlet block is provided with a movable terminal to selectively engage one of three positive junction block terminals. The outlet receptacle block of this prior art arrangement includes a conducting shaft electrically connected to the positive outlet terminal of the outlet receptacle block and to the movable terminal. The movable terminal may be slid upwardly or downwardly to a desired position for engagement with one of three positive connector terminals of the power junction block.
In yet another prior art arrangement disclosed in U.S. Pat. No. 4,781,609, dated Nov. 1, 1988, the outlet receptacle block is provided with a pair of slidable terminals mounted on a carrier to assure synchronous movement of the two contacts. The junction block is provided with a ground terminal, three positive and three common terminals defining three separate circuits with a common ground. The carrier on the outlet receptacle block may be positioned so that one of its terminals engages one of the positive terminals of the junction block and the other engages the corresponding common terminal. A sliding electrical contact internal to the receptacle block provides contact between the movable terminals and corresponding terminals for engagement with the prongs of a standard electrical cord.
In each of the above-mentioned prior art arrangements, an electrical switch contact between a movable part and a stationary part is employed to connect the outlet terminals of the outlet receptacle block to its input terminals engaging the power junction block. A disadvantage of these prior art arrangements is that sliding contacts, particularly in a relatively high current environment, introduce resistance and may fail to provide the proper electrical continuity desired. Furthermore, sliding contacts add to the expense of the outlet receptacle block.